3 Non-social differences

3.1 Repetitive behaviour and routines

Some children incessantly twirl their fingers or flap their hands. Such movements are often known as stimming, because they may play a role in changing sensory stimulation. For instance, moving the hand up and down in front of the face may cause a pleasing change in the pattern of light reaching the eyes. Children may also develop intense preoccupations and obsessions with specific objects or textures, such as running their hand up and down a velvet curtain. They may line up their toys in a repetitive or obsessive way, or insist on wearing the same clothes or eating the same food every day. They may become anxious and distressed if a familiar routine, such as going to school by bus, is disrupted.